Many micropower generation systems, such as those in the home, typically include one or more of a number of solar cells, wind turbines, combined heat and power systems and other similar systems. The micropower generation systems generate electricity. The generated electricity is converted into useable voltage and current suitable for local consumption, for example 240V at 50 Hz or 110V at 60 Hz. However, these micropower generation systems often generate more power than is actually needed for local consumption. If the micropower generation systems were connected to the alternating current (AC) gird, from which power is normally drawn, this surplus power could be sent back to the AC grid.
Micropower generation systems often include inverters that are used to generate an AC output from a direct current (DC) input. The inverters are generally located within the proximity of the power source (solar cells, wind turbine, etc.) and connected to the AC grid mains remotely. Among various inverters, a solar inverter converts the variable DC output of a photovoltaic (PV) solar panel into a utility frequency AC that can be fed into a commercial electrical grid or used by a local, off-grid electrical network.
In recent years there has been a re-emergence of interest in module-integrated electronics. The solar micro-inverter in particular has been noted as a product that has a number of benefits over the existing conventional solutions. A solar micro-inverter converts DC electricity from a single solar panel to AC. The electric power from several micro-inverters is combined and fed into an existing electrical grid. Unlike conventional string inverter devices, each micro-inverter is connected to a single solar panel rather than multiple solar panels.
The benefits of an energy harvesting system based on micro-inverters include: improved energy harvest over the life of the installation, particularly in scenarios of shading or other causes of mismatch in solar PV installations; and low voltage DC (less than 80V from a single panel), which is safer and significantly reduces arcing faults. Additional benefits of an energy harvesting system based on micro-inverters also include the ability to pinpoint failures or problems with solar panels (or solar modules), and the scalability by adding panels to an installation. The installation process itself is also extremely easy and can be considered as a plug and play method. Solar micro-inverters enable true plug and play installation of solar PV modules. The ease with which these can be installed is a major selling point for the solar industry. In the discussion that follows, the term “inverter” is used to describe all electrical power converters that change DC to AC, including string inverters and micro-inverters.
Because the inverters are fed into an existing electrical grid, they have to conform to the grid connection standard used by the local electrical grid. For example, the inverters must synchronize with the frequency of the electrical grid, the AC current produced by the inverters must be within the required voltage range of the grid, and so on. Different countries have different utility requirements. As a result, inverters manufactured for different countries must be configured differently in order to function properly.
Currently, the inverters are configured in the factory, where they are manufactured and labeled. This adds an extra step in the manufacturing process. Moreover, once the inverters are manufactured and configured, they have to be managed separately for different countries or different grid connection standards. The manufactured inverters usually do not go immediately from the factory to the end customer. They are usually stored in several warehouses in different regions around the world, waiting to be ordered and distributed. FIG. 1 conceptually illustrates the current approach of manufacturing and distributing inverters to different countries by configuring inverters at the factory. As shown in the figure, a factory 105 manufactures and configures different inverters based on different grid connection standards for different countries. The configured inverters are stored in two warehouses 110 and 115, and distributed to five different countries, i.e., country 1-5.
The factory 105 produces and configures the inverters 1-5, each of which is configured to comply with a particular grid connection standard of a particular country. For example, the inverter 1 is configured to comply with the grid connection standard of country 1, the inverter 2 is configured to comply with the grid connection standard of country 2, and so on. Once the inverters are produced and configured in the factory 105, they are stored in warehouses 110 and 115. A warehouse stores several different kinds of inverters. Each kind of inverter is configured for the grid connection standard of a particular country. For example, warehouse 110 stores three different kinds of inverters, i.e., inverter 1-3 for country 1-3. The warehouse 115 stores three different kinds of inverters, i.e., inverter 3-5 for country 3-5. Inverters with the same configuration may be stored in different warehouses. For instance, inverter 3 is stored in both warehouses 110 and 115. The different kinds of inverters are distributed to their corresponding countries when ordered by customers. For example, inverter 1 is distributed to country 1; inverter 2 is distributed to country 2, and so on. Because the same kind of inverters may be stored in different warehouses, a country may receive inverters configured to comply with its grid connection standard from multiple warehouses. For instance, country 3 receives inverter 3 from both warehouses 110 and 115.
As illustrated in FIG. 1, in order to ensure sufficient supply for each country and each grid connection standard, the warehouses must carry a lot of different stocks and treat different inverters differently based on demand forecasting and many other factors. When the manufacturer needs to supply inverters to many different countries or different grid connection standards, the management of the inventory and distribution of different inverters become very complicated.